There's already a healthy aftermarket for it. Buschur, AMS, etc, all carry parts for them.
Motor wise, it shares enough similarities that a lot of the mods are going to be very similar to the Evo X. Suspension wise, though, you're going to be limited to fewer options, as it shares the base Lancer's frame, and Evo parts won't work.
The stock turbo is a pretty weak little single scroll, but it takes aftermarket turbos well enough 
Forester XT's are fun too, though.
2008 Evo X. GSR. RR.
Buschur CatBack w/ Bullet Muffler
Buschur Test Pipe
Buschur UICP
Buschur LICP
Buschur Intake/MAF Pipe/Shield
Buschur Evo X FMIC